Idaho researcher helps set up Kenyan spud seed test

By John O’Connell

Capital Press

Published:January 31, 2014 11:23AM

Last changed:January 31, 2014 11:36AM

Submitted by Jonathan Whitworth
Jonathan Whitworth, a research plant pathologist with the USDA's Agricultural Research Service in Aberdeen, Idaho, poses in a seed potato field with a laboratory crew in Molo, Kenya.

Jonathan Whitworth, a potato scientist with the USDA's Agricultural Research Service in Aberdeen, Idaho, found disease-resistant breeding material in Kenya, while helping the African nation establish new disease testing, that he would like to incorporate into his own program.

ABERDEEN, Idaho — Jonathan Whitworth spent much of last summer helping one of the major certified potato seed providers in Kenya establish laboratory testing to back up visual field inspections for diseased plants.

Now Whitworth, a research plant pathologist with the USDA’s Agricultural Research Service in Aberdeen, hopes the Kenyan potato industry will reciprocate by sending breeding cultivars he saw in their fields with late blight resistance, as well as some other virus-resistant lines.

Upon arriving in the U.S., Whitworth explained the cultivars would have to remain in quarantine, undergoing tests for up to a year and a half to confirm they’re clean. He’ll also search for brown rot-resistant material in his own breeding cultivars to help the Kenyans address one of their common diseases.

“It’s something that will disqualify their seed from certification just like bacterial ring rot will disqualify our seed,” Whitworth said, adding that in the U.S. brown rot is most prevalent in Florida.

Whitworth’s trip, from June 10 to July 5, was funded with a U.S. Agency for International Development grant and marked the fifth year of a project in which U.S. researchers offer expertise to improve Kenyan potato production. Oregon State University Extension agronomist Don Horneck made the project’s first trip to Kenya, and a Wisconsin researcher assisted with tissue cultures and laboratory disease detection during in the summer of 2012. The Washington, D.C.,-based nonprofit international development organization CNFA handles the program’s arrangements.

Whitworth helped Kenya’s Agricultural Development Corp., a self-funded governmental agency responsible for about 5 percent of the country’s certified potato seed, to establish a laboratory utilizing enzyme-linked immunosorbent assay testing for six viruses. ELISA tests utilize antibodies and color change to detect the present of pathogens. Backing up visual inspections with testing prevents removal of healthy material that appears to express symptoms and trains the eyes of officials conducting the inspections as to how viruses express themselves among different varieties and in varying conditions, Whitworth said.

He said much of the country’s seed potato supply isn’t certified and comes from farmers directly supplying other farmers.

Potatoes are Kenya’s second largest crop behind maize. Whitworth said they grow mostly round, white-skinned varieties and a few red varieties and plant about 270,000 acres of spuds over two annual growing seasons. Their potato crops are rain-fed. In most fields, he said workers fill 300-pound bags by hand at harvest, setting the bags along the roadside to be trucked away.

Whitworth visited the Kenyan Highlands, where the elevation is 8,200 feet.

“Everywhere you looked, there were potato fields,” he said.

Whitworth hopes to one day return to Kenya.

“Everybody there was so very kind to you,” he said. “They took their personal time to take and show me around, to things like the national parks and out on the savannah.”

Whitworth also hopes to host a Kenyan graduate student in the Pacific Northwest.